A small group of family and friends, including Parker's mother and Hubbard's sister, attended the service.

The ceremony was performed by the Rev. Paul Fromberg, rector of St. Gregory of Nyssa Episcopal Church in San Francisco. The couple chose Thursday as their wedding date because it was the 23rd anniversary of the beginning of their relationship.

"This is a very happy day for us," Parker said in her statement. "We have had to wait a very long time to formalize our commitment to each other. Kathy has been by my side for more than two decades, helping to raise a family, nurture my political career and all of the other ups and downs and life events that come with a committed relationship. She is the love of my life, and I can't wait to spend the rest of my life married to her."

Fromberg is a gay priest who had been rector of St. Andrew's Episcopal Church in Houston before leaving for San Francisco.

Parker's election in 2009 made Houston the largest U.S. city with an openly gay mayor. While California allows gay people to marry, Texas does not recognize same-sex marriages.

According to the mayor's statement, Hubbard will avail herself of other insurance options "and will, therefore, not participate in the new policy granting city health insurance benefits to spouses of legally married city employees."